Answer:
The best example of that is when Hitler occupied Rhineland, which was an area that was demilitarized after war ended and the peace treaty in Versailles was signed. Still, European countries practically didn't react to this act.
Step-by-step explanation:
After Nazis gained power in Germany, they started publicly announcing that they will denounce the Treaty of Versailles. The first step in that direction was the occupation of Rhineland. But the Nazis didn't stop there. Before WW2 started, Germany decided to occupy some other regions, and great powers in general again didn't prevent that.